It is known to mount still and video cameras so that they can record images or video during action sports, for example wearable video cameras can be mounted to a helmet, bicycle, surf board, etc. to capture action footage. So-called “action cams” can typically be mounted in different orientations, e.g. on a helmet, but the orientation of the camera is generally fixed once it has been mounted in a particular position. This can be problematic when activities do not take place on the level and the camera may be tilted or inverted during use. A horizon adjustment may be required to adjust the orientation of the horizontal image plane in relation to the mounting orientation of the camera body, e.g. during post-processing of video data recorded by the camera.
WO 2009/018391 A1 discloses a manual horizon adjustment control in the form of a rotary ring around the lens. Manual rotation of the ring during use of the camera either rotates the CMOS image sensor, so that post-processing is not required, or encodes the video data with the correct horizon so that post-processing adjustment is automatic. However this requires an additional manual adjusting step every time the mounting orientation is changed. WO 2012/037139 A2 shows examples of a camera mounted in different orientations with the lens manually rotated to provide for horizon adjustment.